• Sedimentology and geochronology of holocene paleochannel features in the lower ohio river valley,Indiana.

      Kathryn G.De Rego; Russell Stafford; Mark Cantin (2012-05-21)
      Rivers condition human settlement strategy by determining both the location of aquatic resources and the stability of the landscape. Therefore, understanding where the river was and how quickly it migrated in the past aids in predicting buried site potential. This study investigates the sedimentology and geochronology of paleochannel deposits along the Lower Ohio River floodplain. A series of low, wide swales are prominent features in a series of bottoms in a ~40 km section of the river valley downstream from the Falls of the Ohio. Previous studies in Knob Creek Bottom indicate that one of these paleochannel swales was active during the early Holocene, roughly 10K to 7.4K rcybp. The positioning of the others suggest that they are the remains of a single channel that flowed on the west side of the river valley during the early Holocene. To test this proposition, cores were collected in several locations within and adjacent to prominent swales. The channel is characterized by laminated point bar deposits overlain by overbank sediment containing a heavily weathered Alfisol, Mollisol, or Inceptisol soil with prominent redox mottles. The sediment ranges from silt to silt loam. In some reaches, alluvial fan sediments interfinger with the point bar deposits. Datable organic carbon was found in both point bar and overbank contexts. This study compares the sedimentology, weathering, and age of these channel segments to determine their geomorphic relationship.
    • The effects of a gluteus medius training protocol on muscle activation.

      Dorpinghaus, ND;; Gage MJ;; Dominguese D;; Kingsley D;; Yoder A (2012-05-21)
      Context: Researchers have suggested that a weak or dysfunctional gluteus medius (GM) has been linked to a number of lower extremity injuries. Identifying an appropriate intervention to prevent or correct deficits of the GM and determine associated outcomes has become a subject of increased interest. Objective: To determine if GM training changes lower extremity muscle activation during a dynamic task. Design: Controlled laboratory study Setting: Biomechanics research laboratory. Participants: Eighteen healthy, physically active participants (7 men, 11 women; age = 21.2±2.01yrs; height = 168.39±8.92cm; mass= 77.76±16.39kg) volunteered for the study. All participants served as their own control. Intervention(s): All of the participants completed a six week GM training protocol. Muscle activation of 5 trunk muscles were measured bilaterally before and after the protocol during a single-leg drop landing and normalized. Main Outcome Measure(s): Peak and mean muscle activation was measured 400ms pre- and post-landing. Results: Decreased muscle activation was observed in the right GM [pre-mean (P=.001), pre-peak (P=.007), post-mean (P=.033), and post-peak (P=.045)]. Increased biceps femoris (BF) mean muscle activation was observed on the stance leg pre-landing (p=.044). Conclusions: Six weeks of GM training was enough time to observe improved GM neuromuscular efficiency. The increased BF muscle activation prior to landing suggests participants had an increased feedforward response in preparation for landing. Therefore the combination of improved neuromuscular efficiency and a greater feedforward response suggest pelvic stabilization may be improved during a single-leg drop landing as a result of six weeks of GM training.